As longtime fans are likely aware, Grohl attempted to recruit Novoselić as a full-fledged Foo Fighters member when he was putting the band together; wanting to avoid the inevitable Nirvana comparisons, he declined, but they've drifted into one another's creative orbits on a handful of occasions over the years, with Novoselić joining the group onstage at various points and even contributing bass and accordion to "I Should Have Known," a track from their 2011 Wasting Light LP. He's had his own musical output to pursue in recent months, recording and performing live with his new band Giants in the Trees, but he took a temporary detour for the night on Dec. 5.

"I Should Have Known" wasn't on the agenda when Novoselić joined the Foos in Eugene. Instead, as you can see via the fan-shot footage embedded above, he chipped in during the night's rendition of "Big Me," the band's Top 20 hit from their self-titled 1995 debut. Seeming to enjoy the show as a fan as much as a friend of the band, Novoselić shared a slew of backstage and behind-the-scenes photos from the gig through his Twitter account. Check out a handful of photos and video clips below, and see the rest right here.